Methods for producing three-dimensional components have already been known for a long time.
European patent specification EP 0 431 924 B1, for example, describes a method for producing three-dimensional objects from computer data. A particulate material is thereby applied onto a platform in a thin layer and said platform is selectively imprinted with a binder material by means of a print head. The particulate area, which is imprinted with the binder, adheres and solidifies under the impact of the binder and an additional hardener, if applicable. The platform is subsequently lowered by a layer thickness in a construction cylinder and is provided with a new layer of particulate material, which is also imprinted, as is described above. These steps are repeated until a certain, desired height of the object is reached. A three-dimensional object is thus created from the imprinted and solidified areas.
After its completion, this object, which is produced from solidified particulate material, is embedded in the loose particulate material and is subsequently freed therefrom. This takes place, for example, by means of a vacuum cleaner. Thereafter, the desired objects, which are then freed from the residual powder, e.g., by means of brushing, remain.
Other powder-supported rapid-prototyping processes, such as the selective laser sintering or the electron beam sintering, e.g., in the case of which a loose particulate material is also in each case applied in layers and is selectively solidified by means of a controlled physical source of radiation, also operate in a similar manner.
All of these methods will be combined herein below under the term “three-dimensional print processes”.
In the case of the three-dimensional print process known from the state of the art, the particulate material is typically applied by means of a spreader unit. In the case of a low fill level, this spreader unit must be filled with particulate material from a reservoir.
Different methods and device are known from the state of the art for this purpose.
WO 98/28124 A1, for instance, describes a method, in the case of which the powder material is pushed onto a workspace via a piston and is applied from there via rollers onto the area, which is to be coated.
A device for filling a spreader device is further known from WO 00/78485 A2, in the case of which a reservoir is arranged in an end position of the spreader device thereabove, with said reservoir encompassing a sliding closure, wherein this sliding closure can be opened, if needed, and the spreader device can thus be filled.
A device, in the case of which the conveying of the particulate material out of the reservoir into the spreader device takes place via a conveyor belt, is furthermore known from the same patent application.
WO 2003/97518 further describes the conveying of the particulate material out of the reservoir into the speader system via a slider.
A conveying device, which uses a belt transport system comprising conveyor cages for transporting particulate material to the spreader device, is further known from US 2004/0012112 A1.
A further possibility for conveying particulate material out of a reservoir into a spreader system is described in DE 10 2005 056 260 A1. In the case of a low fill level, the spreader unit is hereby filled with particulate material from a reservoir in such a manner that the fill level in the spreader unit reaches a predetermined level across the entire length of the spreader device even in the case of a previously irregular fill level.
In the case of these methods and devices for filling a spreader unit for fluids, which are known from the state of the art, it has proven to be disadvantageous that one fill level control is always necessary. An uneven filling across the length of the spreader device can furthermore only be compensated for to an unsatisfactory degree with the methods from the state of the art.